17
If the current equalizing resistors are not well matched, it is preferable that the
voltages be slightly unbalanced to achieve current balance. Be sure that the
supplies are adequately balanced so that both remain in the CV mode.
When connected in parallel and operating in the constant current mode, the
voltage controls of both supplies should be preset to the same value. Then when
the load is connected, the current controls of the two supplies should be
adjusted for approximately equal current from each unit. Be sure that both
supplies remain in the CC mode.
5 Remote Operation
The power supply can be connected to the RS232 interface using the 9-pin (DB-9)
serial connector on the rear panel. The 1737 uses a null modem RS232 cable. The
cable pin diagram for the DB-9 connector is shown in the picture below:
2
3
5
RX
TX
GND
DB-9
connector
Instrument
2
3
5
RX
TX
GND
PC
DB-9
connector
Figure 10 - RS232 Cable Pin Diagram
For all communications over the RS232 interface, the power supply uses Xon/Xoff
protocol.
NOTE:
If using HyperTerminal, make sure you properly configure the “ASCII Setup”. In
“ASCII Setup”,
do not append line feeds to “ASCII Sending”
. “Echo typed characters
locally” can be checked, but “Send line ends with line feeds” should be left
unchecked. In “ASCII Receiving”, “Append line feeds to incoming line ends” can also
be checked.
